8AHX

Cryo-EM structure of the nitrogen-fixation associated NADH:ferredoxin oxidoreductase RNF from Azotobacter vinelandii

Summary for 8AHX

• Entry DOI: 10.2210/pdb8ahx/pdb
• EMDB information: 15452
• Descriptor: Ion-translocating oxidoreductase complex subunit A, IRON/SULFUR CLUSTER, FLAVIN MONONUCLEOTIDE, ... (12 entities in total)
• Functional Keywords: metalloprotein, flavoprotein, electron transfer and na+/h+ translocation, membrane protein
• Biological source: Azotobacter vinelandii DJ; More
• Total number of polymer chains: 7
• Total formula weight: 201210.81

Authors

Zhang, L.,Einsle, O. (deposition date: 2022-07-24, release date: 2023-11-01, Last modification date: 2024-10-16)

Primary citation

Zhang, L.,Einsle, O.
Architecture of the RNF1 complex that drives biological nitrogen fixation.
Nat.Chem.Biol., 2024

PubMed Abstract: Biological nitrogen fixation requires substantial metabolic energy in form of ATP as well as low-potential electrons that must derive from central metabolism. During aerobic growth, the free-living soil diazotroph Azotobacter vinelandii transfers electrons from the key metabolite NADH to the low-potential ferredoxin FdxA that serves as a direct electron donor to the dinitrogenase reductases. This process is mediated by the RNF complex that exploits the proton motive force over the cytoplasmic membrane to lower the midpoint potential of the transferred electron. Here we report the cryogenic electron microscopy structure of the nitrogenase-associated RNF complex of A. vinelandii, a seven-subunit membrane protein assembly that contains four flavin cofactors and six iron-sulfur centers. Its function requires the strict coupling of electron and proton transfer but also involves major conformational changes within the assembly that can be traced with a combination of electron microscopy and modeling.

PubMed: 38890433
DOI: 10.1038/s41589-024-01641-1

Experimental method

ELECTRON MICROSCOPY (3.11 Å)